1. Field of the Invention
The present invention relates to vehicle headlight aiming devices, and more particularly to a vehicle headlight aiming apparatus which measures the pattern and intensity of a light beam projected from a vehicle headlight and compares it to one of a plurality of known headlight aiming standards to provide accurate aiming information. The invention includes interchangeable software structure which allows the apparatus to be upgraded to communicate with various software programs and input and output devices.
2. Description of the Prior Art
Vehicle headlight aiming devices are known in the art. For example, U.S. Pat. Nos. 4,948,249 and 5,164,785, which are owned by the assignee of the present invention, disclose two methods of aiming a vehicle headlight. These patents are hereby incorporated into the present patent application by reference.
These types of prior art headlight aiming devices generally include a reflective surface and a lens for focusing a headlight beam on the reflective surface,a light sensing device for measuring the pattern and intensity of the reflected lightbeam, and a comparator for comparing the reflected lightbeam to a known headlight aiming standard. If the headlight is improperly aimed, the comparator provides an error message including corrective instructions The operator then mechanically adjusts the headlight until its light beam is properly aimed.
Although prior art headlight aiming devices provide for accurate headlight measurement, they suffer from several limitations which limit their utility. For example, prior art devices cannot easily switch from one known headlight aiming standard to another. Various headlight aiming standards exist for cars manufactured in different countries and for different types of vehicles manufactured in the U.S. For example, headlights of vehicles manufactured in the U.S. are often aligned in accordance with standards set by the Society of Automotive Engineers (SAE). In contrast, many European manufactured vehicles have headlights with distinctly different beam patterns that require a different aiming standard.
The comparators of prior art devices typically include software containing a single headlight aiming standard. Often the headlight aiming standard is stored on an EPROM computer chip which is directly connected to the motherboard of the comparator. Thus, if the operator of prior art headlight aiming device wishes to switch from one standard to another, he must take the comparator apart and change EPROM chips. This operation is time consuming and difficult for mechanics lacking computer experience. This operation is also dangerous because it exposes the mechanic to electrical shocks. Moreover, frequent switching of EPROMs often damages the internal circuitry of the aiming device.
A similar disadvantage of prior art headlight aiming devices is that they do not utilize headlight aiming standards written in languages other than English. Since many mechanics are fluent in languages other than English, these prior art devices are difficult to use.
Another drawback of prior art headlight aiming devices is that they cannot be easily upgraded to communicate with various software and different types of external devices. Prior art headlight aiming devices typically include a standard RS232 serial port for coupling with external devices. Although this serial port allows limited communication with external devices, it cannot be upgraded to allow additional communication capabilities.
Thus, the prior art points out the need for an improved headlight aiming device which overcomes these and other limitations.